Protecting and improving water

The importance of agriculture and food production to the Irish economy has come sharply into focus once more in recent years. Indeed, one of the few genuinely bright spots on our economic horizon since the onset of the global recession has been the stellar performance of the Irish food industry on both the home and international markets.

Everything comes at a price, however, and agricultural production by its very nature makes use of fertilisers which contain large amounts of nitrogen and phosphorus and produces by-products such as pig slurry which require careful management to prevent pollution of our rivers and groundwater.

The EU Nitrates Directive has the objective of reducing water pollution caused or induced by nitrates from agricultural sources and preventing further pollution. The primary emphasis of the directive is on the management of livestock manures and other fertilisers.

The result of the directive is strict limits on the amount of nitrogen from livestock manure per hectare which farmers can apply each year. Also controlled are the timing and procedures for the land application of fertilisers, limits on the land application of fertilisers that are consistent with good agricultural practice, storage requirements for livestock manure, and general provisions on storage management.

But there is little point in imposing these restrictions on farmers if they are not going to work and have a measurable impact on water quality. For this, among other reasons, the Department of Agriculture, Food and the Marine has funded the Agricultural Catchments Programme (ACP), run by Teagasc, which is working with 300 farmers across six river catchments around the country to evaluate the environmental and economic effects of the measures being implemented under the Nitrates Directive.

The twin aims of the ACP are the protection and improvement of water quality and the provision of support for the production of high-quality food.

Nitrates directive
"This is very much a participatory research project involving 300 farmers in different areas of the country," says ACP manager Ger Shortle. "What it all stems from is concerns about nitrates in water which go back to the 1950s and 1960s when there was a big push to increase agricultural production. The Nitrates Directive was originally adopted in 1991 and was implemented in Ireland in 2006 and is supposed to deliver better quality water for human consumption."

Ireland is unusual among EU member states in that it has implemented the directive throughout the entire country and not just in specific regions or zones and it has included phosphorus in the regulations. “Nitrogen is not really a problem in Ireland,” Shortle explains. “Phosphorus is a major concern for water quality, however. We have had lakes in the north-east of the country which were eutrophied as a result of phosphorus as far back as the 1970s.”

The first phase of the ACP study began in 2008 and concluded at the end of 2011 and the report of this work has been submitted to the Department of Agriculture, Food and the Marine. The second phase, which will take the project up to the end of 2015, is currently under way.

One of the key outcomes from the first phase has been the findings in relation to the long lead time between actions taken now and measurable impacts on water quality. “There is a very long lag between what farmers are doing now and the benefits from it,” says Shortle.

“There are very few immediate cause and effects which can be measured. If a farmer spreads slurry and this is followed by a massive storm you may get some run-off but that’s not the case with phosphorus or nitrogen-based fertilisers.”

Indeed, the time lag between cause and effect with those two elements can be generational in length. “If you have phosphorus in a field which is above safe levels it can take anywhere between five and 30 years to run it down to a level which is safe. With nitrogen it depends on the local geology and the soil but it can take up to 20 years to run down. We know enough now not to expect overnight success and it will take up to 20 years for the directive to make a real difference.”

This means the measures introduced under the directive have to be given time to work.

Interestingly, one of the biggest challenges facing Irish agriculture is not excess phosphorus but the fact that two-thirds of Irish farmland is deficient in it. “We have an index with four classifications with four being excessive and one being deficient. Between 18 per cent and 20 per cent of Irish agricultural land is index 4 and that’s come down from around a third during the past seven years so we have seen a clear improvement there. The single most important change we have seen in that respect is improvements in the management of phosphorus by farmers.”

It turns out that phosphorus is relatively easy to manage. If a farmer calculates that his crops or animals or produce are going to export a certain amount of phosphorus each year the same amount needs to be imported. “It is possible to achieve a good balance when it comes to phosphorus,” Shortle says.

Economic benefits
Nitrogen is altogether more difficult to manage because of its labile nature. This means that it is liable to change and be easily altered. "It can go off as a gas, it can be bound in the soil, it can be mobile in the soil, it can run off in water. A farmer can plough up an old piece of grassland which hasn't been used for years and can get a release of nitrogen that was bound up in the soil. It can become mobile very easily. But one of the advantages we have as a country is that our landscape has considerable natural denitrification properties and this is one of the reasons why nitrogen hasn't posed a particular problem here."

The good news from the research is that fertiliser management in Ireland is improving and this will have economic benefits for farmers in terms of reducing the amount of fertiliser they need to use. “The research will help farmers get a better bang for their buck in terms of fertiliser use and will assist in protecting and improving the quality of our water in the longer term.”